Supported catalysts for the production of 4-methyl-pentene from propylene

ABSTRACT

Supported catalysts containing alkali metal for the production of 4-methyl-1-pentene from propylene and a process for their production by heating previously dried support particles in an inert gas atmosphere for at least about 30 minutes at a temperature of at least about 150*C, mixing the support particles obtained with a compound of a transition metal that is thermally decomposable at below about 400*C and an alkali metal and heating the mixture obtained for about 1 to 120 minutes in an inert gas stream to about 150* to 500*C.

United States Patent [191 Forni et a1.

[ SUPPORTED CATALYSTS FOR THE PRODUCTION OF 4-METHYL-PENTENE FROMPROPYLENE I [75] Inventors: Lucio Fomi; Renzo Invernizzi, both of Milan,Italy [73] Assignee: Societa Italiana Resin S.I.R. S.p,A.,

Milan, Italy [22] Filed: Aug. 6, 1973 [21] Appl. No.: 385,769

[30] Foreign Application Priority Data Sept. 20, 1972 Italy 29423/72[52] US. Cl 252/440, 252/447, 252/459, 252/476 260/683.15 E

[51] Int. Cl Blj 11/82 [58] Field of Search 252/440, 447, 459, 476;260/683.15 E

[56] References Cited UNITED STATES PATENTS 3,331,884 7/1967 Yeo et al260/683.l E

[ Dec. 10, 1974 3,389,190 6/1968 Alderson etal 260/683.15E 3,622,648ll/l97l Schlomer et al. 260/283.l5 E 3,756,963 9/1973 Fomi 260/683.l5 E

Primary Examiner-W. Cannon Attorney, Agent, or Firm-Sughrue, Rothwell,Mion, Zinn & Macpeak 1 v {5 7] ABSTRACT 11 to minutes in an inert gasstream to about to 500C.

10 Claims, No Drawings SUPPORTED CATALYSTS FOR THE PRODUCTHON OF4-METHYL-PENTENE FROM PROPYLENE The invention relates to new supportedcatalysts containing alkali metal, a process for their production, andtheir use for the production of 4-methyl-l-pentene from propylene.

It is known that 4-methyl-l-pentene can be used for the production ofpolymers characterized by high crystallinity and transparency, excellentmechanical and electrical properties, and high stability and resistanceto chemicals. These poly-(4-methyl-l-pentenes) are advantageously usedfor the production of moulded articles such as containers and packagingmaterial for foods and parts for electrical equipment. The polymers of4-methyl-l-pentene are normally prepared by polymerization of themonomer with the aid of Ziegler-- Natta catalysts; cf. Encyclopedia ofPolymer Science and Technology, Interscience Publishers, New York,London, Sydney, Vol.7 (1967), pages 764-765; Vol.9 (1968), Page 446, andVol. 13 (1970), page 20, and Belgian Patent No. 616 564. A particularlypure 4-methyl-l -pentene should be used for the preparation of thepolymers having the properties described above, especially having highcrystallinity andtransparency.

It is known that 4-methyl-l-pentene can be prepared by dimerization ofpropylene in the presence of catalysts consisting of an alkali metalapplied to a support. Examples of supports that are particularlysuitable for these catalysts are graphite, potassium carbonate, alkalimetal silicates, alkali metal halides, magnesium sulphate, and talc.Furthermore, US. Pat. No. 3,175,020 discloses a process for theproduction of 4-methyl-lpentene which comprises contacting propene at apressure in the range from about to 105 atm (150 to 1,500 p.s.i.g.) andat a temperature in the range from about 65 to 205C (150 to 400 F) witha dimerization catalyst consisting essentially of potassium metaldisposed upon substantially anhydrous alumina, having a surface areabelow about 20 square meters per gram.

However, the known processes have the disadvantage that the yield of thepropylene dimerization and the selectivity for 4-methyl-l-pentene arerelatively low. Considerable quantities of other isomers of 4-methyl-l-pent'ene, such as cis-4-methyl-2-pentene,trans-4-methyl-2-pentene, 2-methyl-l-pentene, 2-methyl-2-pentene,l-hexene, cis-2-hexene, trans-2 hexene, cis-3-hexene, and trans-3-hexeneare formed in addition to 4-methyl-l-pentene.

Though special measures have been taken in the production of thecatalysts in order to improve them, conversions of about 40 percent inthe dimerization of propylene and selectivities of about 80 percent for4-methyl-l-pentene are attained only in exceptional cases. The valuesnormally reached are only 25 to 35 percent for the conversion and 50 to65 percent for the selectivity. Expensive operations are thereforenecessary for the recycling of unreacted propylene to the dimerizationreactor and purification of the reaction product. Because of the largequantity of by-products, it is sometimes even necessary to isomerize'thebyproducts to the desired product.

One purpose of the invention is therefore to provide new catalysts forthe production of 4-methyll -pentene with which a high conversion in thedimerization of propylene and a high selectivity for 4-methyll -penteneare obtained. Another purpose of the invention is to provide a processfor the production of these new catalysts. Finally, it is a purpose ofthe invention to provide an improved process for the production of4-methyl-lpentene from propylene using these new catalysts, which giveshigher conversions of propylene and higher selectivity for 4-methyl l-pentene.

The object of the invention is thus a process for the production ofsupported catalysts containing alkali metal, characterized in that a.previously dried support particles are heated in an inert gas atmospherefor at least about 30 minutes to a temperature of at least about 150C,

b. the support particles obtained in accordance with a) are mixed with acompound of a transition metal that is thermally decomposable at belowabout 400C and an alkali metal in a quantity such that the total weightof alkali metal and of the transition metal compound, both calculated asthe weight of metal, is about 1 to wt. percent based on the weight ofthe support, the atomic ratio of alkali metal to transition metal beingin the range between about 50 l and l 1, and

c. the mixture obtained in accordance with b) is heated for about 1 tominutes to about to 500C in an inert gas stream with stirring.

With the catalysts of the invention, a yield of generally more than 40percent in the dimerization of propylene and a selectivity for4-methyl-l-pentene of generally at least 80 percent are achieved.

In the process of the invention, a support in a divided form that hasbeen dried for at least about 5 hours, preferably about 12 hours, attemperatures of about 100 to 150C is used. The commonly used supports,preferably graphite, potassium carbonate, alkali metal silicates, alkalimetal halides, magnesium sulphate, or talc, may be used as supports.Potassium carbonate is preferably used as the support. The driedparticles of support are then heated in a stream of inert gas for about30 minutes, preferably about 2 hours, to a temperature of at least about150C. Anhydrous nitrogen is normally used as the inert gas, and theoptimum temperature for the treatment of the previously dried supportparticles is about 250C. The support is in form of irregular particlesof a size of 0.25 to 5 mm. The preferred size is about 1 mm.

Still in the stream of inert gas, the particles of support are mixedwith the alkali metal and the thermally decomposable compound transitionmetal in the proportions given above.

The alkali metal used is preferably metallic sodium or potassium, whichis previously carefully cleaned and stored under an inert solvent suchas xylene. The pre ferred thermally decomposable transition metalcompounds are compounds of gold, nickel, chromium, palladium, cobalt, ortungsten.

In a preferred embodiment of the invention, the support is potassiumcarbonate, which, after predrying and heat treatment, is mixed with thealkali metal and the transition metal compound in a quantity such thatthe total weight of the alkali metal and the transition metal compound,both calculated as the weight of metal, is about 1 to 30 wt. percentbased on the weight of support. Moreover, the transition metal compoundis used in a quantity such that the atomic ratio of transition metal toalkali metal is in the range between about 1:50 and 1:1, preferably.about 1:15 to 1:5. The thermally decomposable transition metal compoundsused in accordance with the invention are preferably salts, oxides, orhydroxides of these metals that decompose below about 400C. Specificexamples of such com- 15 minutes, cooled to 100C, and then mixed with0.6 g of metallic sodium that has been carefully purified and storedunder anhydrous xylene. Still in a stream of anhydrous nitrogen and withcontinuous stirring, the

pounds are the oxides, acetates, carbonates, oxalates, 5 mixture isheated to 300C until the alkali metal is comnitrates, benzoates,cyanides, halides, and transition pletely dispersed in the mass. Thecatalyst obtained is metal ammine complexes, i.e., complexes of thetransicooled and introduced into a tubular reactor in an inert tionmetals with ammonia and amines, such as tetramgas atmosphere.

mineplatinum hydroxide or diammineplatinum nitrite. Propylene isintroduced into the reactor at a rate of One or more of these compoundsmay be used 1 volume of liquid propylene per volume of catalyst per in apreferred embodiment of the process of the inhour and dimerized at atemperature of 150C and a vention, the transition metal compound isadded to the P e e 0f 70 aim The experiment is Continued for 9 supportat temperatures of about 100 to 240C with hoursstirring and in a streamof inert gas. The temperature EXAMPLE 2 0f mass is then lowered to themelting Point of the E5 The catalyst is prepared in accordance withExample alkali fneta] selectedj 0 the alkall metai added to 1, but 552 gof dried potassium carbonate, 0.455 g of the mlxmle with Surfing and mmen g atmo- Ni(CH COO) .4l-1 O, and 0.51 gof metallic sodium are sphere.The mixture is then heated for about 1 to 120 d minutes, preferablyabout 10 to 90 minutes, at about EXAMPLE 3 O 0 O O 150 to 500pre.fe.rab]y about 220 350 The catalyst is prepared in accordance withExample Under these conditions the decomposition product of l, but 5.52g of dried potassium carbonate, 0.419 g of the transition metal compoundprobably reacts with the CNCH C00) and 0 51 of metallic sodium r dalkali metal and is very finely distributed on the support 3 g a e usetogether with the alkali metal, i.e., the reaction product EXAMPLE 4 ofthe decomposed trans1t1on metal compound and the v sodium metal isdistributed in an active form on the sur- The Catalyst pfepared Inaccordance with Example face, including the pore surfaces, of thesupport. After but g of dned potasslum carboniitei -1 g of cooling, thecatalyst is ready for use. The finished cata- (H5103 and 1 g of metallicSodium am lyst is preferably stored and handled under nitrogen or useEXAMPLE some other inert gas. This also apphes to introduction into thedimerization reactor The catalyst is prepared in accordance with ExampleThe dimerization of propylene with the catalysts prebut g of [in-edPotassium carbonate, 0-456 8 of pared in accordance with the inventionis carried out :1 2- 2 and g of metallic Sodium in the same manner aswith the known supported cataare usedlysts containing alkali metal by aknown method. The EXAMPLE 6 d1mer1zat1on of propylene to4-methyl-l-pentene w1th the catalysts of the invention is preferablycarried out The catalyst P P m accordance Wlth Example with a propylenethroughput of about 0'] to 50 VOL 1, but 5.52 g of dned potassiumcarbonate, 0.406 g of umes of liquid propylene per volume of catalystper HZWO and g of melaulc Sodlum are usedhour at temperature of about100 to 250TC and at EXAMPLE 7 pressures of about 20 to 350C atm. INparticular, the I process of the invention is carried out attemperatures The catalyst is piepared m.accordance Wnh Example of about150C, pressures of about 70 atm, and a feed g g of dned potassmm F l0498 g of rate of about 1 volume of liquid propylene per volume M 2 andg of metallic sgdlum are used of catalyst per hour. COMPARISON EXAMPLEThe examples illustrate the invention without limiting it. Forcomparison, a conventional catalyst is prepared 1n a known manner from5.52 g of potassium carbonate EXAMPLE 1 and 0.51 g of metallic sodium.

10 g of potasslurn carbonate are dried for 15 to 18 The catalysts of theinvention prepared in accorhours at 120C. 5.52 g of this dried potassiumcarbondance with Examples 2 to 7 and the conventional cataate are heatedin a stream of anhydrous nitrogen for 1 lyst prepared in accordance withthe Comparison Exhour at about 280C. After cooling to 120C, thepotasample are used for the dimerization of propylene in acium carbonateis mixed with 0.915 g of AuH(N a)4- 55 cordance with Example 1. Theresults are shown in 3H O. The mixture is heated to 240C over a periodof Table I.

Table 1 Catalyst Conversion Selectivity for Selectivity for Selectivityof example of propylene 4-methyl-l-pentene other isomers for higher- Wm(/71 1%) boiling products ('1 1 56.5 29.5 20.5 traces 2 41 a3 17 do. 345.5 86.5 13.5 (it). 4 49.5 78 22 dd. 5 3e 87 13 dd. 6 41.5 89.5 11.5d0. 7 40 86 14 d0. Comparison example 10 80 19.5 0.5

The superiority of the catalysts of the invention can be seen from TableI.

What we claim is:

1. Process for the production of a supported catalyst containing alkalimetal for dimerization of propylene to 4-methyl-l-pentene, characterizedin that a. previously dried support particles are heated in an inert gasatmosphere for at least about 30 minutes to a temperature of at leastabout 150C,

b. the support particles obtained in accordance with a) are mixed with acompound of a transition metal that is thermally decomposable at belowabout 400C, said compound being one of gold, nickel, chromium,palladium, cobalt or tungsten, and an alkali metal in a quantity suchthat the total weight of alkali metal and of the transition metalcompound, both calculated as the weight of metal, is about 1 to 80 wt.percent based on the weight of the support, the atomic ratio of alkalimetal to transition metal being in the range between about 50 l and l l,and

c. the mixture obtained in accordance with b) is heated for about 1 to120 minutes to about 150 to 500C in an inert gas stream with stirring todecompose the transition metal compound.

2. Process in accordance with claim 1, characterized in that graphite,potassium carbonate, an alkali metal silicate, an alkali metal halide,magnesium sulphate, or talc is used as the support.

3. Process in accordance with claim 1, characterized in that sodium orpotassium is used as the alkali metal.

4. Process in accordance with claim 1, characterized in that thetransition metal compound and the alkali metalare used in an atomicratio of about 1:15 to 1:5.

5. Process in accordance with claim 1, characterized in that the mixtureof the support, the alkali metal, and the thermally decomposabletransition metal compound is heated for about 10 to minutes totemperatures of about 220 to 350C.

6. Process in accordance with claim 1, characterized in that in step a)support particles are used which have been dried for at least about 5hours at temperatures of about to C.

7. Process in accordance with claim 1, characterized in that in step a)the heating of the dried support particles is carried out for about 2hours at a temperature of about 250C.

8. Process in accordance with claim 1, characterized in that the supportis potassium carbonate which, after predrying and heat treatment, ismixed with the alkali metal and the transition metal compound in aquantity such that the total weight of the alkali metal and thetransition metal compound, both calculated as the weight of metal, isabout 1 to 30 wt. percent based on the weight of the support.

9. Process in accordance with claim 2, characterized in that potassiumcarbonate is used as the support.

10. Process in accordance with claim 6, characterized in that in step a)support particles are used which have been dried for at least about 12hrs. at said temperatures.

1. PROCESS FOR THE PRODUCTION OF A SUPPORTED CATALYST CONTAINING ALKALIMETAL FOR DIMERIZATION OF PROPYLENE TO 4-METHYL1-PENETENE, CHARACTERIZEDIN THAT A. PREVIOUSLY DRIED SUPPORT PARTICLES ARE HEATED IN AN INERT GASATOMOSPHERE FOR AT LEAST ABOUT 30 MINUTES TO A TEMPERATURE OF AT LEASTABOUT 150*C, B. THE SUPPORT PARTICLES OBTAINED IN ACCORDANCE WITH A) AREMIXED WITH A COMPOUND OF A TRANSISTION METAL THAT IS THER MALLYDECOMPOSABLE AT BELOS ABOUT 400*C, SAID COMPOUND BEING ONE OF GOLD,NICKEL, CHROMIUM, PALLADIUM. COBALT OR TUNGSTEN, AND AN ALKALI METAL INA QUANTITY SUCH THAT THE TOTAL WEIGHT OF ALKALI METAL AND OF THETRANSISTION METAL COMPOUND, BOTH CALCULATED AS THE WEIGHT OF METAL ISABOUTT 1 TO 80 WT. PERCENT BASED ON THE WEIGHT OF THE SUPPORT, THEATOMIC RATION OF ALKALI METAL TO TRANSITION METAL BEING IN THE RANGEBETWEEN ABOUT 50 : 1 AND 1 : 1, AND C. THE MIXTURE OBTAINED INACCORDANCE WITH B) IA HEATED FOR ABOUT 1 TO 120 MINUTES TO ABOUT 150 TO500*C IN AN INERT GAS STREAM WITH STIRRING TO DECOMPOSE THE TRANSITIONMETAL COMPOUND.
 2. Process in accordance with claim 1, characterized inthat graphite, potassium carbonate, an alkali metal silicate, an alkalimetal halide, magnesium sulphate, or talc is used as the support. 3.Process in accordance with claim 1, characterized in that sodium orpotassium is used as the alkali metal.
 4. Process in accordance withclaim 1, characterized in that the transition metal compound and thealkali metal are used in an atomic ratio of about 1:15 to 1:5. 5.Process in accordance with claim 1, characterized in that the mixture ofthe support, the alkali metal, and the thermally decomposable transitionmetal compound is heated for about 10 to 90 minutes to temperatures ofabout 220* to 350*C.
 6. Process in accordance with claim 1,characterized in that in step a) support particles are used which havebeen dried for at least about 5 hours at temperatures of about 100* to150*C.
 7. Process in accordance with claim 1, characterized in that instep a) the heating of the dried support particles is carried out forabout 2 hours at a temperature of about 250*C.
 8. Process in accordancewith claim 1, characterized in that the support is potassium carbonatewhich, after predrying and heat treatment, is mixed with the alkalimetal and the transition metal compound in a quantity such that thetotal weight of the alkali metal and the transition metal compound, bothcalculated as the weight of metal, is about 1 to 30 wt. percent based onthe weight of the support.
 9. Process in accordance with claim 2,characterized in that potassium carbonate is used as the support. 10.Process in accordance with claim 6, characterized in that in step a)support particles are used which have been dried for at least about 12hrs. at said temperatures.